In the optical fiber fields, signals are in pairs and matched with each other, one for transmitting, and one for receiving. Optical transmission tools for optical fibers may be used to connect several short optical fibers with each other to form a long optical fiber. The optical transmission tools may be also used for connecting the optical fiber to an active component, e.g., a light source or a detector, or to a passive component, e.g., a light switch or an attenuator.
In an optical fiber connector known to the inventor, the fiber core of the optical fiber can be coupled with the optical path of a connecting component. Hence, the optical fiber is detachably inserted into an adapter. In order to prevent dusts entering into the adapter to damage or affect the optical fiber inside the adapter when the adapter is not plugged by the connector, a shielding piece is provided and pivotally connected to the adapter.